"Holiness deals with the thoughts and intents, the purposes, the aims, the objects, the motives of men. Morality does but skim the surface, holiness goes into the very caverns of the great deep; holiness requires that the heart shall be set on God, and that it shall beat with love to him. The moral man may be complete in his morality without that.
Methinks I might draw such a parallel as this. Morality is a sweet, fair corpse, well washed and robed, and even embalmed with spices; but holiness is the living man, as fair and as lovely as the other, but having life. Morality lies there, of the earth, earthy, soon to be food for corruption and worms; holiness waits and pants with heavenly aspirations, prepared to mount and dwell in immortality beyond the stars. These twain are of opposite nature: the one belongs to this world, the other belongs to that world beyond the skies.
It is not said in heaven, "Moral, moral, moral art thou, O God!" but "Holy, holy. holy art thou. O Lord!" You note the difference between the two words at once. The one, how icy cold; the other, oh, how animated! Such is mere morality, and such is holiness! Moralist! — I know I speak to many such — remember that your best morality will not save you; you must have more than this, for without holiness — and that not of yourself, it must be given you of the Spirit of God — without holiness, no man shall see the Lord."
Seen at the desiringGod blog